The addon is simple and easy to use.
1. Select an an animated armature/mesh/curve
2. Use the operator Detect Hold Frames
The addon detects changes from frame to frame and bakes in the camera offset while the selected object is in a hold frame. The result is an empty that only moves to follow the camera when the animated object is in a hold frame. When you parent your armature or mesh/curve to the empty it will make the hold frames of the object look static to the camera.
The other operator is to for fixing any errors or to make a change to the bake afterwards. When you run the operator it will clear the selected empty to the world center and then bake forward the camera offset for the set amount of frames. This way you can force the camera offset if the detection fails.